1. Field of the Invention
The present invention relates to a lithography mask and an optical lithography method using surface plasmon, and more particularly to a lithography mask and an optical lithography method using surface plasmon suitable for applying in the case where a fine pattern a length of which is shorter than that of light wavelength, for example, a fine pattern of nanometer order is transferred onto a resist.
2. Description of the Related Art
It is known that a well-known optical lithography which has heretofore been known involves such a problem that when the minimum dimension of an opening in a lithography mask which was formed into a desired pattern with openings becomes a half or less than a wavelength of light to be applied, the light is diffracted, so that the pattern of the lithography mask cannot be correctly transferred to a resist.
As a means for solving such well-known problem in optical lithography, for example, near field lithography is known.
In the near field lithography, a lithography mask is disposed in closely contact with a resist, and an evanescent field appeared in an opening, a dimension of which is smaller than that of a wavelength of light, is used for sensitizing the resist, openings being formed as a pattern on the lithography mask. However, the near field lithography involves such a problem that electric field strength of near field light oozed from the openings is small so that an exposure time of the resist becomes long in addition to such a problem that an adjustment for closely contact alignment of the resist and the mask is difficult.
It is to be noted that the prior art which has been known by the present applicant at the time of filing this application is that as described above, so that there is no prior art information to be described herein.